Comprehensive comparison of macro-strain mode and displacement mode based on different sensing technologies. (January 2015)

• Record Type: Journal Article
• Authors: Hong, Wan; Zhang, Jian; Wu, Gang; Wu, Zhishen
• Is Part Of: Mechanical systems and signal processing. Volume 50/51(2015)
• Page Start: 563
• Page End: 579
• Publication Date: 2015-01
• Subjects: Distributed sensing -- Measurement error -- Macro-strain mode -- Displacement mode -- Structural health monitoring; Structural dynamics -- Periodicals; Vibration -- Periodicals; Constructions -- Dynamique -- Périodiques; Vibration -- Périodiques; Structural dynamics; Vibration; Periodicals; 621
• DOI: 10.1016/j.ymssp.2014.05.011
• Languages: English
• ISSNs: 0888-3270

Abstract

Abstract: A comprehensive comparison of macro-strain mode and displacement mode obtained from distributed macro-strain sensing and high-density point sensing (such as accelerometers) technologies is presented in this paper. Theoretical derivation reveals that displacement mode shape from accelerometers and modal macro-strain from distributed macro-strain sensors can be converted into each other. However, it is realized that displacement mode shape as global behavior of a structure can still be calculated with high-precision from modal macro-strain considering measurement errors in practical monitoring, whereas modal macro-strain can hardly be accurately achieved from displacement mode shape when signals are corrupted with noise in practical monitoring. Simulation and experiment results show that the calculated displacement mode shapes are very close to the actual ones even if the noise level reaches 5%. Meanwhile, damage index using measured modal macro-strain is still effective when the measurements are corrupted with 5% noise which is reliable for damage detection in practical monitoring. Calculating modal macro-strain from noise-polluted displacement mode shape will cause an unacceptable error if the noise level reaches only 0.5%, which has been verified in the simulation. Highlights: Comprehensive comparison of macro-strain mode and displacement mode. Macro-strain mode and displacement mode can be converted into each other. Calculating displacement mode considering measurement errors. Calculating macro-strain mode considering measurement errors. Damage indices using measured and calculated modal macro-strain.